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| Titel |
Statistics of Severe Tornadoes and Severe Tornado Outbreaks |
| VerfasserIn |
B. D. Malamud, D. L. Turcotte |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250059386
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| Zusammenfassung |
| The standard measures of the intensity of a tornado in the USA and many other
countries are the Fujita and Enhanced Fujita scales. These scales are based on the
damage that a tornado causes. Another measure of the strength of a tornado is its path
length of touchdown, L. In this study we consider 4,061 severe tornadoes (defined as
L -¥ 10 km) in the continental USA for the time period 1981-2010 (USA Storm
Prediction Center Severe Weather Database). We find for individual severe tornadoes:
(i) The noncumulative frequency-length statistics of severe tornado touchdown
path lengths, 20 < L < 200 km, is well approximated by an inverse power-law
relationship with exponent near 3. (ii) There is a strong linear scaling between the
number of severe tornadoes in a year and their total path lengths in that year. We
then take the total path length of severe tornadoes in a day, LD, as a measure of
the strength of a 24-hour USA tornado outbreak. We find that: (i) On average, the
number of days per year with at least one continental USA severe tornado (path
length L -¥ 10 km) has increased 16% in the 30-year period 1981-2010. (ii) The
daily numbers of severe tornadoes in a USA outbreak have a strong power-law
relationship (exponent 0.87) on their daily total path lengths, LD, over the range
20 < LD |
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